Examples of known display devices are described in Patent Documents 1 and 2. Patent Document 1 describes a display device including a switching element for video signal selection which selectively connects an arbitrary source line to one of a plurality of video signal supply lines, a scan signal selection element which selectively connects an arbitrary gate line to one of a plurality of scan signal supply lines, a plurality of external signal connection terminals, and a plurality of inspection terminals. Inspection switching elements are connected to each of the plurality of video signal supply lines, and the plurality of inspection switching elements have input terminal sides connected in parallel and connected to a first inspection terminal and have control terminal sides connected in parallel and connected to a second inspection terminal, and a plurality of color selection signal supply lines are connected to a plurality of third inspection terminals, and the plurality of scan signal supply lines are connected to a plurality of fourth inspection terminals.
Patent Document 2 describes a following display device. A halfway section of a video signal wiring group lead out of a source driver between its routing position and an external connection terminal corresponding to the driver is separated, and the separated video signal wiring group is arranged as a bypass wiring group on a surface of a counter electrode substrate opposed to a liquid crystal layer. Bypass electrodes at both ends of the bypass wiring group and bypass electrodes at two ends of remaining video signal wiring groups left by parting the video signal wiring group on an array board are connected in series through a conductive member buried in a seal material. Further, the source driver on the array board and the corresponding bypass wiring group on the counter substrate are put one over the other along the width in plan view of the panel.